1. Field of the Invention
The invention generally relates to a bicycle derailleur protection device, and in particular it relates to a guard that a user can mount onto a bicycle to protect the rear derailleur from external debris and damage.
2. Description of the Related Art
As more and more Americans have become aware of the numerous health benefits provided by regular exercise, recreational bicycling has become increasingly popular. In recent years, many areas in public places such as parks have been dedicated as bicycle paths in order to accommodate interested bicyclists. The wide variety of available bicycle designs has allowed enthusiasts to enjoy bicycling over terrains of all types, from suburban sidewalks to rocky mountains.
Many bicycles contain several gears that provide different gear ratios to adapt to different torque/speed requirements. In order to provide different gear ratios during pedaling, a plurality of different sized chain sprockets are mounted for rotation along the axes of the rear hub and the pedal shaft of the bicycle. Typically, there are two or three different sized chain sprockets, known as chain rings, rotatable along the axis of the pedal shaft and six or seven different sized chain sprockets, known as freewheel cogs, mounted in spaced relation on a free wheel and rotatable along the axis of the rear hub. The freewheel cogs are arranged such that those with the largest diameters are on the inside while others are located toward the outside in order of decreasing diameters. The number of available gear ratios increases with the number of chain rings and cogs that are provided.
It is necessary to move the chain from one freewheel cog to another and/or from one chain ring to another in order to change gears. This operation is performed by a front derailleur associated with the chain rings and a rear derailleur associated with the free wheels. A conventional rear derailleur includes a clamping assembly which secures the derailleur to a rear drop-out or rear axle holder of the bicycle frame, a chain cage which moves the chain from one cog to another and a controller which connects the chain cage to the clamping assembly and actuates the chain cage to control the latter to move the chain from one cog to another.
However, an acute and potentially dangerous problem arises when proper operation of the front or rear derailleurs of a bicycle is impaired. This situation can develop under a variety of circumstances. For example, a user can drive his bicycle through an area that contains fresh mud or wet soil that can stick to the derailleurs. Alternatively, a biker can ride his mountain bicycle through a region in which there are fallen tree limbs or pebbles that get caught up in components of the derailleurs. Moreover, significant damage to a derailleur can easily result when a user accidentally drops the bicycle on its side or prevailing winds blow it over. Hence, there is a pressing need for an easily mountable and removable device that covers a derailleur without interfering with the mechanical operation of the bicycle or diminishing a rider's enjoyment thereof.
U.S. Pat. No. Des. 323,309 to Perry (“Perry”) teaches an ornamental design for a bicycle freewheel gear cover. However, a gear cover having the design of Perry would be bulky and cumbersome since it would have multiple tiers of concentric circles.
U.S. Pat. No. 1,325,206 to Raybon (“Raybon”) discloses a driving gear casing for bicycles. However, the driving gear casing of Raybon does not shield a rear derailleur.
U.S. Pat. No. 4,044,621 to McGregor et al. (“McGregor”) teaches a sprocket structure and chain guard. However, the apparatus of McGregor also does not shield a rear derailleur.
U.S. Pat. No. 5,540,118 to Calendrille (“Calendrille I”) teaches a flexible bicycle derailleur cover. However, the derailleur cover of Calendrille I is unduly complicated and confusing.
U.S. Pat. No. 6,203,459 B1 to Calendrille (“Calendrille II”) teaches another bicycle derailleur cover. However, the derailleur cover of Calendrille II is also unduly complicated and confusing.
U.S. Pat. No. 6,332,853 B1 to Bowman (“Bowman”) teaches a removable and flexible cover for a bicycle drive train. However, the cover of Bowman is not specifically configured to shield a rear derailleur.
While these devices may be suitable for the particular purposes employed, or for general use, they would not be as suitable for the purposes of the present invention as disclosed hereafter.